Spin-orbit coupling-enhanced valley ordering of malleable bands in twisted bilayer graphene on WSe2
Abstract Recent experiments in magic-angle twisted bilayer graphene have revealed a wealth of novel electronic phases as a result of interaction-driven spin-valley flavour polarisation. In this work, we investigate correlated phases due to the combined effect of spin-orbit coupling-enhanced valley p...
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| Format: | Article |
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Nature Portfolio
2023-07-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-023-39855-x |
| _version_ | 1827905370638516224 |
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| author | Saisab Bhowmik Bhaskar Ghawri Youngju Park Dongkyu Lee Suvronil Datta Radhika Soni K. Watanabe T. Taniguchi Arindam Ghosh Jeil Jung U. Chandni |
| author_facet | Saisab Bhowmik Bhaskar Ghawri Youngju Park Dongkyu Lee Suvronil Datta Radhika Soni K. Watanabe T. Taniguchi Arindam Ghosh Jeil Jung U. Chandni |
| author_sort | Saisab Bhowmik |
| collection | DOAJ |
| description | Abstract Recent experiments in magic-angle twisted bilayer graphene have revealed a wealth of novel electronic phases as a result of interaction-driven spin-valley flavour polarisation. In this work, we investigate correlated phases due to the combined effect of spin-orbit coupling-enhanced valley polarisation and the large density of states below half filling of the moiré band in twisted bilayer graphene coupled to tungsten diselenide. We observe an anomalous Hall effect, accompanied by a series of Lifshitz transitions that are highly tunable with carrier density and magnetic field. The magnetisation shows an abrupt change of sign near half-filling, confirming its orbital nature. While the Hall resistance is not quantised at zero magnetic fields—indicating a ground state with partial valley polarisation—perfect quantisation and complete valley polarisation are observed at finite fields. Our results illustrate that singularities in the flat bands in the presence of spin-orbit coupling can stabilise ordered phases even at non-integer moiré band fillings. |
| first_indexed | 2024-03-13T00:41:40Z |
| format | Article |
| id | doaj.art-789672dcee27490b8d97ce15521650ef |
| institution | Directory Open Access Journal |
| issn | 2041-1723 |
| language | English |
| last_indexed | 2024-03-13T00:41:40Z |
| publishDate | 2023-07-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Nature Communications |
| spelling | doaj.art-789672dcee27490b8d97ce15521650ef2023-07-09T11:18:41ZengNature PortfolioNature Communications2041-17232023-07-011411810.1038/s41467-023-39855-xSpin-orbit coupling-enhanced valley ordering of malleable bands in twisted bilayer graphene on WSe2Saisab Bhowmik0Bhaskar Ghawri1Youngju Park2Dongkyu Lee3Suvronil Datta4Radhika Soni5K. Watanabe6T. Taniguchi7Arindam Ghosh8Jeil Jung9U. Chandni10Department of Instrumentation and Applied Physics, Indian Institute of ScienceDepartment of Physics, Indian Institute of ScienceDepartment of Physics, University of SeoulDepartment of Physics, University of SeoulDepartment of Instrumentation and Applied Physics, Indian Institute of ScienceDepartment of Instrumentation and Applied Physics, Indian Institute of ScienceResearch Center for Functional Materials, National Institute for Materials ScienceInternational Center for Materials Nanoarchitectonics, National Institute for Materials ScienceDepartment of Physics, Indian Institute of ScienceDepartment of Physics, University of SeoulDepartment of Instrumentation and Applied Physics, Indian Institute of ScienceAbstract Recent experiments in magic-angle twisted bilayer graphene have revealed a wealth of novel electronic phases as a result of interaction-driven spin-valley flavour polarisation. In this work, we investigate correlated phases due to the combined effect of spin-orbit coupling-enhanced valley polarisation and the large density of states below half filling of the moiré band in twisted bilayer graphene coupled to tungsten diselenide. We observe an anomalous Hall effect, accompanied by a series of Lifshitz transitions that are highly tunable with carrier density and magnetic field. The magnetisation shows an abrupt change of sign near half-filling, confirming its orbital nature. While the Hall resistance is not quantised at zero magnetic fields—indicating a ground state with partial valley polarisation—perfect quantisation and complete valley polarisation are observed at finite fields. Our results illustrate that singularities in the flat bands in the presence of spin-orbit coupling can stabilise ordered phases even at non-integer moiré band fillings.https://doi.org/10.1038/s41467-023-39855-x |
| spellingShingle | Saisab Bhowmik Bhaskar Ghawri Youngju Park Dongkyu Lee Suvronil Datta Radhika Soni K. Watanabe T. Taniguchi Arindam Ghosh Jeil Jung U. Chandni Spin-orbit coupling-enhanced valley ordering of malleable bands in twisted bilayer graphene on WSe2 Nature Communications |
| title | Spin-orbit coupling-enhanced valley ordering of malleable bands in twisted bilayer graphene on WSe2 |
| title_full | Spin-orbit coupling-enhanced valley ordering of malleable bands in twisted bilayer graphene on WSe2 |
| title_fullStr | Spin-orbit coupling-enhanced valley ordering of malleable bands in twisted bilayer graphene on WSe2 |
| title_full_unstemmed | Spin-orbit coupling-enhanced valley ordering of malleable bands in twisted bilayer graphene on WSe2 |
| title_short | Spin-orbit coupling-enhanced valley ordering of malleable bands in twisted bilayer graphene on WSe2 |
| title_sort | spin orbit coupling enhanced valley ordering of malleable bands in twisted bilayer graphene on wse2 |
| url | https://doi.org/10.1038/s41467-023-39855-x |
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